Screw-machine



(N ormodel.) 2 sheets-sheet 1. A. JOHNSTON.

SCREW MACHINE Patented May 17, 1881.

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2 Sheets- Sheet 2.

(No Model.)

A. JOHNSTON.

SCREW MACHINE No. 363,144. Patented May-17, 18s-7..

nur mmm UNITED STATES PATENT Orricn,

ALLEN JOHNSTON, OF OTTUMWA, IOVA.

SCREW-MACHINE.

SPECIFICATION forming partof Letters Patent No.363,144, dated May 17, 1587.

i Application filed November 1l, 188,6. Serial No. 218,571. (No model.) i

To all whom, it may concern:

Be it known that I, ALLEN JOHNSTON, a citizen of the United States, residing in Ottumwa, in the county of VVapello and State of Iowa, have invented Va new and useful Improvement in Screw-lllachines, of which the following is a specification. A

My invention relates to metalscrew machines, and more particularly to the chuck and mechanism for operating the chuck by which the rod is held while the work is being done in such machines. In such machinesthe wedge or inclines at the end of the chuckspindle, against which the chuck-jaws operate, usually or necessarily taper outward from a larger to a smaller diameter at the eXtreme rnd of thespindle, the interior surface of the wedges being ordinarily in the shape of a frustnm of a cone with the small end outward. As, the chuck-spindle usually revolves with great rapidity, this increased interior diameter of the spindle or wedges at a point back from the end of the spindle produces by centrifugal action a suction and tendency to draw air, dust, and small chips or metal particles, as well as the oil or lubricant, into and through the hollow chuckspindlc, and great difficulty has heretofore been experienced in the practical operation of such machines, owing to the metal chips and particles becoming jammed up and wedged in the chuck-spindle, so as to interfere with the 4feed of the rod through the same and with the operation of the chuck.

To overcome this difficulty-and herein my invention in `part consists-I provide Vthe chuck-spindle with one or more radial or lateral discharge-openings communicating with the interior of the chuck-spindle, through which any particles that may be drawn into the chuck-spi ndle may be discharged or thrown out by centrifugal action. These openings are preferably located back of the inelines or wedges which operate the chuckjaws.

A further improvement of this feature of my invention consists in providing, the interior of the ehuelcspindle, just back of the inclines or wedges, with an enlargement, preferably a conical recess inclined in the opposite direction to the wedges or inclines, into which the discharge-openings lead at or near the point of largest diameter. By thnsinclining the interior of the spindle in the opposite directionto the incline of the wedges the centrifugal action tends to collect the dirt and particles at the point of largest diameter, or near the discharge-openings, .and thus facilitates their discharge yfrom the spindle.

Another feature of my invention consists in the improved means I employ for operating the chuck, or for opening` and closing the chuckjaws upon the rod or stock. Heretofore, in order to allow and compensate for the inequalities in the size ofthe rod 0r stock, the chuck-jaws have usuallybeen closed `upon the rod by a spring; or, if the jaws have been closed by positive mechanism or a positive movement, as shown and described in my patent, No. 316,788, of April 28, 18851, a springhas been interposed to allow for the varying size of the rod or stock.

In the practical operation of these machines it is very important that t-he Vrod or stock be always and certainly held very tightly and firmly in the chuck-jaws, and that said jaws be compressed upon the stock with the proper degree of pressure every time, in order to prevent breakage, injury to the tools, Snc. The rod or stock operated upon frequently varies from one sixty-fourth to one thirty-second of an inch in size. Vhere the degree of compression of 'the chuekjaws depends,either directly or indirectly, upon a spring, it is always more or less unreliable, and necessarily exertsdifferent degrees of pressure with every variation in the size of the stock; and if the variation in the size of the stock happens t0 be considerable, especially if the springs get a little out of their exact proper adjustment, injury is liable to occur to the machine or tools.

By my present improvement I close the chuck-jaws by positive mechanism, and no spring of any kind is interposed between the chuck-spindle and its operating-sleeve as a cushion for such sleeve, so that the jaws may be closed with precisely the same force upon the rod or stock whatever its size.

present improvement the chuck-jaws are reeiprocated lengthwise in the chuck-spindle by means of a positively-driven revolving screwthreaded sleeve, the threads of which. engage corresponding threads in the chuClLspindle.

In my This screw-threaded sleeve is revolved in the same direction as the chuck-spindle, but at different rates of speedmthat is to say, it is driven faster than the chuck-spindle when operating to close the chuck-jaws and slower than the chuck-spindle when operating to r'elease them, or vice versa, according as the screw-threads connecting said sleeve with the chuck-spindle are left-hand or right-hand threads. Rotary motion is communicated from the chuck-spindle to this threaded sleeve by means of suitable gears and clutch mechanism, or other equivalent or substitute mechanism for communicating rotary motion to the threaded sleeve from the chuck-spindle to drive said sleeve at different rates of speed when operating to close and when operating to releasethe chuck-jaws. This connecting meehanism, or that part thereof which operates the revolving threaded sleeve to elose the chuckjaws, is furnished at some point therein or at some part thereof with a friction device or connectionsuch as a friction-gear, frictionwheel, or an ordinary belt and pulley-which will slip as soon as the chuck-jaws are closed with the sufficient or required degree of force upon the stock, and thus compensate for variations or inequalities in the size of the stock.

My invention also consists in the Vnovel devices or parts and novel combination of devices or parts herein shown and described andmore particularly set forth in the claims.

In the accompanying drawings, which form a part of this specification, and in which similar letters of reference indicate like parts, Figure l is a centralvertical longitudinal sec tion of a machine embodying my invention, and Figs. 2 and 3 are sections on lines 2 2 and 3 3 of Fig. l.

In said drawings, A represents the frame of the machine.

B is the hollow chuck-spindle, suitablyjournaled thereon; and B', the d riving-belt pulleys. The chuckspindle is furnished at its outer end with wedges or inclines b for operating the chuck-jaws o, consisting, preferably, of aninteriorly-eone-shaped thimble screwed in the end of the spindle.

The chuck-jaws are or may be of the ordinary eonstruetion, consisting, preferably, of a spring-metal sleeve split longitudinally the greater portion of its length and fitting in the hollow chuck-spindle, B.

The chuck-spindle B is furnished with one or more, preferably several, holes or other openings, b', extending laterally therethrough,

l through which particles drawn into the chuckspindle will be thrown out by centrifugal actionr In addition to the openings b, I also ings b. It is preferable that the diameter of this recess b2` should exceed the interior diameter of the wedges or cone-thimblc b at its inner or larger end, as thereby any tendency of metal particles to lodge in orupon the face ot' the wedges b, and thus interfere with the operation of the chuck, is avoided.

C is a sleeve fitting within the chuck-spindle B, and by which longitudinal movement is communicated from the positively-driven revolving threaded sleeve D to the chuck-jaws c, and the latter forced against the wedges or inclines b to close the jaws upon the stock. The threaded sleeve D abuts against the end of the sleeve C, and it is connected by screwthreads l d with the spindle B, or with a nut or sleeve, ci', rigidly secured on vthe end of said spindle. By this means, while the operating sleeve or screw D may revolve independently of the chuck-spindle B and of the chuckjaws c or their sleeve C, the chuck-jaws have a perfectly rigid and unyielding longitudinal connection with said operating sleeve or screw D, so that the chuck -jaws must necessarily have the same longitudinal movement imparted to them as is imparted to said sleeve D., I do not here refer toA the return movement of the chuck-jaws, but to their forward movement, by which they are closed upon the rod or stock and kept closed while the work is being done.V

It will be observed that the end of the independently-revolving operating-sleeve D abuis directly against or is in contact with the end of the sleeve C, by which the longitudinal motion of the sleeveD is communicated to the chuck-jaws c, thus making a posit-ive and unyielding connection between the chuck-jaws and the operating screw or sleeve D. This abutting ofthe end of the sleeve D against the chuck-jaw sleeve C is a simple form of rigid connection between the two, and by which the forward movement ofsaid sleeve D will he positively imparted to the ehuck-jawswithout alteration or diminution. Any other suitable form of rigid and unyielding connection bctween the sleeve D and the chuck-jaws c may, however, be employed. In this way, when the chuck-jaws are once closed upon the stock or rod, as the mechanism which holds the .jaws closed is of a rigid, aositive, and unyield- IIO the rod will be firmly held while the work is y threads d d are left-hand threads. Right-handrthreads may, however, be employed; but in such case the sleeve D should be driven faster than the spindle B to release thechnck-jaws, and slower to close them. As illustrated in the drawings, with left-hand threads d el the sleeve D is driven faster than the chuck-spindle to push the sleeve forward and close the chuck-jaws, and slower than said spindle to release them or withdraw the sleeve B from the end of sleeve C as the spindle B revolves from left to right.

F is a shaft having a friction-gear, f, which meshes with a gear, f', on the chuck-spindle B, and by or through which frictiongear motion is communicated to the rotary threaded sleeve D when the same is operating to close the clutch-jaws.

The gear f may preferably be cut upon the outer surface of the threaded nut or sleeve d'. The friction-gear f is adj ustably clamped between the friction-disks ff on the shaft F by means of the threaded nut f4, and disks of papiemnach or other material, f 5, should be interposed between disks fzf3 and wheel f. The disk f2 is keyed rigidly to the shaft F.

G G are clutch-sleeves, having ordinary clutch faces or notches at their outer'ends adapted to engage corresponding clutches, g g', secured rigidly to the shaft F. The clutchsleeves G G are suitably journaled on the frame of the machine, and the shaft F tits loosely in said sleeves, so that it may slide longitudinally thereon and rotate freely therein when neither of the clutches G g or G g' is engaged. The clutch-sleeve G is furnished with a gear, g2, which meshes with a gear, g3, on the screw-threaded sleeve D. The size of the gears g2 g3 is such in relation to the size of the gear ff that the sleeve D will be driven slower than the spindle B when the sleeve G is clutched to the shaft F, and thus operate the left-hand screw-threads d d to open the chuck-J- aws. The clutch-sleeve G is furnished with a gear, g", which meshes with a gear, g5, secured to the threaded sleeve D. The sizeof the gears 'g4 g5 is such in relation to the size of the gears ff," that when thesleeve Gis clutched to the shaft F the threaded sleeve D will be driven faster than the spindle B, and thus cause the left-hand screw-threads d l to force forward the same and close the chuck-jaws. The shaft F is reciprocated longitudinally to bring the clutches g g alternately into engagement with one or the other of the clutches G G', or into engagement `with neither of said clutches, at intervals, as required, in the operation of the machine, by means of a cam-wheel, H, on the shaft H', which cam-wheel has a peripheral groove, h, that operates a sliding bar, h', connected by an arm, h2, to the shaft F. The shaft F, 'or the clutch-sleeve g secured thereto, is provided with a circular'groove, h3, in which the end of the arm 71jZ lits. The camshaft H ,isL driven from the chuck spindle through a train of red uci ng intermeshin g gears, h4, h5, 7i, LT, hs, ha, hw, h, hw, and h, or other suitable or equivalent mechanism.

The spindle B, or the threaded nut d se cured thereto, and the sleeve D, or a collar, d', secured thereto, are each provided with projecting stop-pins d3 d?, to limit the extent the sleeve D may revolve in relation to the spindle B to a little (or the thickness of the stoppins) less than one complete revolution.

In operation the machine is set or adjusted so that one turn of the sleeve D will move the sleeve C sufficiently to close thel chuck-jaws properly upon the rod or stock, even if the same is comparatively small in size. If the stock is somewhat larger, the sleeve D makes correspondingly less than a complete revolution, the friction-wheel f slipping as 'soon as the required force is exerted upon the chuckjaws. After the stock or rod has been fed forward, the chuck-jaws being then open, the cam H moves the shaftF in the direction to clutch the gear g2 thereto, and thus drive the threaded sleeve D in the direction necessary to move the sleeve C forward and close the chuck-jaws upon the stock. The cam H holds the clutches G g thus in engagement until the sleeve D makes about one complete revolution, the friction-wheelf slipping after the jaws are closed with sufficient force. After the sleeve D has thus made one complete revolution to close the chuck-jaws, the cam H moves the shaft F into its midway position, as indicated in Fig. l, so that neither of the clutches G g G g is engaged, and holds said shaft in this position While the work is being done by the tools upon the end of the rod or stock. At this time, while the work is thus being done, the shaft F is free to revolve, and the chuckspindle receives little retardation from the mechanism. After the work is completed upon the end of the rod, the cam G moves the shaft F so that the clutches G g are engaged, and the sleeve D thus revolved to unthread or withdraw itself from the spindle B and permit the clutch -jaws to open. The clutch-jaws c and the sleeve C are retracted by the spring action of the jaws as soon as the threaded sleeveD is withdrawn.

Vhile the frictiongear f or other equivalent friction device may be located at any point in the connecting mechanism by or through which motion is communicated from the spindle B to the sleeve D, itis, however, preferable to and one minor feature of my invention consists in locating or combining this friction device, whether it be friction-gear, frictionwheel, friction belt and pulley, or other friction mechanism, in direct connection with the revolving spindle itself, so that there will be as little as possible interinediale friction of parts to overcome before the friction device is reached in communicating motion from the spindle to the sleeveiD. By this means the friction device is made more sensitive to act the moment the chuck-jaws exert the proper pressure upon the stock.

In the drawings, K represents the toolholder turret, slides, and mechanism for bringing the several tools successively in to operation, and L represents a feed tube or device for feeding the rod or stock forward through the chuck. This tool-holder mechanism may be of any ordinary or desired construction, and as my present invention does not relate particularly thereto this part of the machine need not be described in detail. Its construction is well known, and one form'of the same is fully shown and described, for eX- ample, in lny prior patent before referred to, No. 316,788. Y

It will of' course be observed that the discharge-openings b in the spindle may extend outward through the spindle or its parts in any desired direction. I prefer to incline them more or less forward, so as to direct, the metal particles forward away from the spindle as they 'are thrown out by the rapid revolution of' the spindle.

'Ihe stops d dL1 on the spindle B and screwsleeve D serve to make the reverse or nnscrewing revolution of the sleeve D on the spindle B always equal to its forward revolution. Il' these stops were not there, the screw would, in running out, run a whole revolution or more, and if the next time the rod or stock were a little smaller it would only close down one complete revolution, and wouldI not close on the smallerstock. These pins or stops are not so much for the purpose of limiting the inward as the outward travel of the screw.

AMy present invention is not only applicable to metal-screw machines, but also to other machines wherein a revolving chuck is employed-as, for example, in machines for turning or forming various shaped articles from the end of a metal rod or bar.

I wish it to be distinctly understood that in the specification and claimsI mean by useof the phrase said screw D, having a rigid or unyielding connection with said chuck-jaws,

or similar phrases, in referring to the screw or sleeve D, that the connection or device which is interposed between said screw and said chuckjaws, or used tocommunieate motion from said" screw to said chuck-jaws, must be a rigid or non-yielding connection or device, as contradistinguished from a spring or yielding device. The end ofthe screw-sleeve D might abut directly against the end of the chuckjaws c, and thus, by this direct abutting of the one against the other, there would be a nonyielding or rigid connection between the two, so that the motion communicated to thescrew would be communicated positively and unyieldingly to the chuck-jaws; or, as shown in the drawings, a sleeve, as C, may be interposed between the screw and chuck-jaws, and thus form a rigid and unyielding connection between the screw and chuck-jaws; or any suitable equivalent device may be employed in place ofthe sleeve C for communicating motion positively and unyieldingly from the screw to the chuck-jaws, so that 'after the ychuck-jaws shall be once firmly closed upon the rod or stock they will be so held firml y and rigidly without possibility of yielding while the rod or stock is being operated upon by the tools` an interior enlargement or recess back of said inclines or wedges, and one or more dischargeopenings leading through the spindle into said recess or interior enlargements, substantially as specified. f

t 3. A revolving chuck-spindle having inclines or wedges t'or operating the chuck-jaws and an oppositely-inclined or'cone surfaced recess back of said inclines or wedges, and provided with one or more discharge-openings leading therefrom through the wall of' the spindle, substantially as specified.

4. The combination, with a chuck-spindle, of inclines or wedges, chuckjaws having an opening or openings between them, and one or more discharge-openings, through which dust or metal particles may be thrown out from the spindle by centrifugal action, Substantially as specified.

5. The combination, with a revolving chuckspindle and its inclines or wedges, of` a sleeve provided with chuck-jaws, and a revolving sleeve loosely screwed upon the end of the chuck-spindle and in contact with the sleeve carrying the chuck-jaws, so that the chuckjaws, after being closed by axial movement of the revolving sleeve, are trmly held thereby, substantially as specified.

6. The combination, with arevolving chuckspindle and its inclines or wedges, of' a sleeve provided with chuck-jaws, a revolving sleeve loosely screwed upon the end of the chuckspindle and so geared thereto that its speed may be greater or less than that of the chuckspindle, and in contact with the sleeve carrying the chuck-jaws, which, having been closed e by axial movement of the revolving sleeve, are firmly held, and connecting mechanism, including a friction-gear, through which motion is communicated from the chuck-spindle to the said revolving sleeve, substantially as speciied.

7. The combination, with a'revolving chuckspindle and its inclines or wedges, of chuckjaws and a rotary screw, as D, having a' iongitudinally rigid or unyielding threaded bearing or nut, in which said serew'turns and`by which it is movedaXially or longitudinally, as in the chuck-spindle, said screw communieating with the chuck-jaws through a rigid or unyielding device, so that the ehuck-jaws, after being closed by the axial movement of' said rotary screw, are rmly held thereby, substantially as' specified.

8. The combination, with a revolving chuckspindle and its inclines or wedges, of chuckjaws and a rotary screw, as D, having a 1ongitudinall y rigid or unyieldin g threaded bearing, in whichsaid screw turns and by which it IIO is moved axially or longitudinally, as in the chuck-spindle, said screw communicating with the chuck-Jaws through a rigid or unyielding device, so that the chuck-jaws, after being closed by the axial movement of' said rotary screw, are firmly held thereby, and mechanism for communicating rotary motion to said screw D, furnished with a friction or yielding device, substantially as specified.

9. The combination7 with a chuck-spindle and its inclines or wedges, of chuck-jaws, a rotary screw for closing said chuck-jaws, and mechanism for revolving said screw, having a friction or yielding device, through which power is communicated to said screw, substantially as specified.

10. The combination, with a revolving chuck-spindle and its inclines or wedges, of' chuck-jaws, a rotary screw for closing said chuck-jaws, and a train of gears for'eommunicating motion from said spindle to said screw, said train being furnished with a friction-gear adapted to slip after the jaws have been closed with sufficient force upon the stock, substantially as specified.

11. The combination, with a revolving chuck-spindle and its inclines ory wedges, of chuck-jaws, a rotary screw for closing said chuck-jaws, and a train of gears for communicating motion from said spindle to said screw, said train being furnished with a friction-gear adapted to slip after the jaws have been closed with sufficient force upon the stock, said friction-gear meshing directly with a gear on the said spindle, substantially-as specified.

12. In a chuck, the combination, with the chuck-jaws, of' a rotary screw having a longitudinally rigid or unyielding threaded bearing, 1n which said screw turns and by which it 1s moved axially or longitudinally, said screw communicating with the chuck-jaws through a rigid or unyielding device, so that the chuckjaws, after being closed by the longitudinal movement of said screw, are rml y held thereby, substantially as specilied. v

13. In a chuck, the combinatiom'with the chuck-jaws, of a rotary screw having` a longitudinally rigid or unyielding threaded bearlng, in which said screw turns and by which it is moved axially or longitudinally, said screw communicating with the chuck-jaws through a rigid or unyielding device, so that the chuckjaws, after being closed by the longitudinal movement of said screw, are firmly held thereby, and mechanism for driving said screw, furnished with a friction or yielding device, substantially as specified.

14. In a chuck, the combination, with the chuck-jaws, of a rotary screw having a longitudinally rigid or unyielding threaded bearing, in which said screw turns and by which it is moved axially or longitudinally, said screw communicating with the chuck-jaws through arigid or unyielding device, so that the chuckjaws, after being closed by the longitudinal movement of said screw, are held firmly thereby, and a train of' gears furnished with a friction-gear for communicating motion to said screw, substantially as specified.

l5. In a chuck, the combination, with the spindle and its inclines, of' the chuck-jaws, a rotary screw, and a train of gears furnished with a pair of clutches and two gear-wheels of different sizes, one for revolving said screw faster and one slower than the spindle, said train being also furnished with a friction-gear, substantially as specified. v

16. The combination, with a chuck-spindle having inclines b,`ot` chuck -jaws c, sleeve C, screw-sleeve D, gear f, friction-gear f, shaft F, clutches G g and G g', gears g2 gi and g4 g5, and a cam, H, and connections for sliding said shaft F, substantially as specified..

17. The combination, with a chuck-spindle, B, of inclines or wedges b, chuck-jaws c, sleeve C, and screw-sleeve D, threaded upon said spindle B, and having its end in contact with the end of said sleeve U, substantially as specified.

18. The combination, with chuck-spindle B, of inclines b, chuck-jaws c, sleeve D, pins or projections on said spindle and said screw-sleeve to limit the relative movement of the latter in respect to the former, and mechanism for communicating motion to said Vsleeve from said spindle, substantially as specified..

19. The combination, with the chuck-spindle B,ofinelines b, chuck-jaws c, sleeve C, screwsleeve D, and pins or projections on said spindle and said screw-sleeve to limit the independent movcment of the latter, and a train of gears furnished with two clutches and gears of different sizes for communicating a faster or slower motion to said screw-sleeve than said spindle, substantially as specified.

20. In an automatic screw-machine, the combination of chuck-jaws and a chuck-spindle with ascrew for opening and closing the chuckjaws, which screw is threaded into or carried by the chuck-spindle at the same speed as the chiickspiiitlle while it is holding the rod from which the screw is formed, and is adapted to be revolved slower or faster to open and faster or slower to close the chuck jaws, stops to limit thetravel of the screw in relation to the chuck-spindle, and mechanism for. automatically revolving said screw, substantially as specified.

21. In an automatic screw-machine, the com- -bination of a revolving chuck-spindle carrying chuck-jaws, a rotary screw for closing said chuck-jaws, and a train of gears for communicating motion from said spindle to said screw, substantially as specified.

22. In an automatic screw-machine, the combination of a revolving chuckspindle carrying chuck-jaws, a rotary screw for closing said chuck-jaws, and a train of gears for communicating motion from said spindle to said screw, and stops to limit the rotation of the screw in relation to the chuck-spindle, substantially as specified. Y

IOO

23. The co1nbination,with thechuei-spindle spindle, said trainbeing also furnished with B, 0f inclines I), chuck-jaws c, sleeve C, screwa friction gear or wheel, substantially as speci- [o l sleeve D, and pins or projections on said spinfied. die and said screw-sleeve to limit the inde- 5 pendent movement of the latter, and ,a train ALLEN JOHNSTON' of gears flirnished with two clutches and gears Witnesses: of diifercnt sizes for communicating a faster or H. M. MUNDAY, slower motion to said screw-sleeve than said LEW. E. CURTIS. 

